The present disclosure relates to a method for designing a multiple tuned filter (hereinafter, referred to as ‘MTF’) according to characteristics of a high voltage direct current (hereinafter, referred to as ‘HVDC’) system.
In a HVDC system, a harmonic filter prevents harmonics generated in power conversion through the operation of a converter from being introduced into an AC system, and also serves as a reactive power supply source in consumption of reactive power. A majority of current type HVDC systems operates with 12 pulses, and hence generates characteristic harmonics of 12 n±1 orders such as 11th, 13th, 23rd, and 25th orders. Particularly, since magnitudes of 11th- and 13th-order harmonics are large, 11th- and 13th-order filters are used to decrease the magnitudes of the 11th- and 13th-order harmonics.
In the current type HVDC systems, a majority of converters operate with 12 pulses. In an 80 kV 60 MW HVDC system currently installed in Jeju, Korea, a converter is also configured as a 12-pulse converter using a serial connection of two 6-pulse groups.
In the HVDC system, a single tuned filter (STF) or double tuned filter (DTF) is widely used as the harmonic filter. Formulae for serial and parallel impedances of the filter may be used to design the filter.
The design of a filter is made by passive calculation based on design ratings or performances of passive elements included in the filter. Therefore, any accurate, efficient, and standardized manner or method does not exist.